Fuse



A. E. DAUM.

I FUSE. APFLICATIQN FILED .IUNEY, I919.

1,378,330. mama May 17,1921.

UNITED STATES ALBERT F. DAUM, OI PITTSBURGH, IENNSYLVANIA.

rusn.

Specification of Letters Patent.

Patented May 17, 1921.

Application filed June 7, 1919. Serial No. 302,370.

To all whom it may concern:

Be it known that I, ALBERT F. DAUM, a citizen of the United States, residing at Pittsbur h, in the county of Allegheny and State of Tennsylvania, have invented certain new and useful Improvements in Fuses, of which the following is a specification.

This invention relates to improvements in fuses, pertaining more particularly to structures of this type capable of replacing the fusible element at will.

The present invention is designed to meet the demands of a field heretofore closed to the use of the inclosed type of fuse, due to the fact that the surrounding conditions were such that disrupting of the fusible element would entail no damage excepting to open the circuit. For instance, in plants where no inflammable material existed in the neighborhood of the fuse-board, the general practice is to simply place the fusible element between the clamping members of the switch-board or other point, leaving the element entirely exposed; or the fuserblocks were inclosed in a cabinet, etc., where the disruption would be ineffective to-provide damage to the surroundings. In such cases it is the practice to save the cost of inclosed fuses,

etc, simply using the fusible elementitself and substituting a new one each time the one in service was blown or disrupted.

While such practice is common it has its disadvantages. For instance, the workman, in making the substitution should, for safety, throw the switch before attempting to connect the element in position in order to prevent receiving shocks; this is overlooked in many instances and the workman has received the effects of the line current through accident. And in some cases fusible elements have blown at the time substitutions or inspections were being made, in which case the effects of'the explosion were dangerous to the workman duetoj-the factthat it took place directly in front of his face.

The present invention is designed to meet this and other objectionable features by the use of a simple form of fuse having the advantages of the'direct contact of the fusible element with the clips or clamps, and which can be employed without additional cost excepting for the initial installationsubse- 'quent renewals being ofthe fusible element itself similar to the present practice. The

additional cost is based on the use of a casing of simple form which protects the intermediate portionof the fusible element while permitting the ends of the element to be exposed for contact with the clips.

To these and other ends, therefore, the nature of which will be readily understood as the invention is hereinafter disclosed, said invention consists in the improved construction and combination of parts hereinafter fully described, illustrated in the accompanying drawings, and more particularly pointed out in the appended claims.

In'the accompanying drawings, in which similar reference characters indicate similar parts in each of the views,

Figure 1 is a longitudinal sectionalview of a fuse according to the present invention. Figs. 2, 3 and 4 are perspective views showing the manner of introducing the fusible element. i uFig. 5 is a perspective view of a completed se. Fig. 6 is a detail section of a modification. Fig. .7 is a fragmentary perspective view showing the use of a retaining band for the strip ends.

While the invention may be variously provided, the preferred form employs but two elements, a tubular casing 10- of insulating material, such, for instance, as fiber, porcelain, glass, etc, and the fusible element 11 of strip form.

The casing is open-endedin its simplest formalthough not limited in this respect, as an end-cap 12 may be employed, if desired. The casing is slitted or kerfed inwardly from its opposite ends, as at 10 the "ends of the fusible element extending positioned therein by any suitable method or manipulation, Figs. 2 to 4 showing a simple way in which this can be. done.

7 As shown in Fig. 2, the ends of the strip are first bent at an angle to the intermediate portion, as indicated for instance by end of the element may have sufficient length to permit its completely surrounding the casing, the excess then being returned to the interior through the slit, as in Fig. 1. This leaves thefuse in the condition shown in Fig. 3.

The partially open end is then again bent into its angular position-the inserted intermediate portion being turned so as to aline the projecting end of the element with the slit which it is to enter during the bending operation-thus introducing such end into its position in the slit, whereupon it is in turn carried around the periphery of that end of the casing, andif the end is of sufficient lengthreentered into the slit and thereby anchoring the fusible element in position within the'casing with the intermediate portion properly supported.

As will be understood, this not only provides a proper support for the intermediate portion of the fusible element, but also provides a metallic annular portion external of the casing suitable to be entered into the clipsas with an ordinary inclosed fuse carrying end-caps-with the direct advantage, however, that there is no possibility of inefficient service through failure to properly bring an end cap into, proper contact with the fusible element (one of the sources of trouble in the inclosed type of fuses), since the contact for the clip is the fusible element itself.

When placing in service, it is necessary only for the workman to place the prepared casing in the clips, this being done without damage to the fusible element or danger to the Workman, since the disrupting portion of the fuse is located within the casing itself, and any explosion that might occur would be expended through the open ends of the casing and away from the workman. An additional advantage lies in the fact that the bend if pressed tightly togetherincreases the cross-section and tends to de- "crease liability of blowing adjacent the ends, in addition to which the element is liability of producing an are between the clips is practically eliminated.

As will be understood, the additional cost 7 is practically. limited to the initial cost-the stored to position.

l Vhile not necessary, some users desire the presence of end caps and these can be employed, if desired, by simply providing a slit 12 in the skirt, the cap being placed in position after the element end has "been inserted in the casing slit and before being carried around the casing periphery-the cap being positioned so that the element end also passes through the cap slit, after which the projecting end is carried around the periphery of the cap instead of the casing. And, if desired, this arrangement can be further amplified by placing an additional member 13 about the exposed end of the elementin which case the element end need not extend entirely around the-periphery of the cap; element 13 may be ofsuitable type, asfor instance a resilient member or clip. And it will be obvious that-this latter may be employed without the end cap.

However, cap 12 and member 13 are simply additions to the preferred form of fuse, and used only where it may 'be-desired to prevent actual freedom of outlet of the gases produced by the disruption of the element.

Vhile I have herein disclosed various ways in which the present invention may be carried into effect, it will be readily understood that changes or modifications therein may be found desirable or necessary in meeting the exigencies of use, and I desire to be understood as reserving the right to make any and all such changes or modifications therein as may be found desirable or necessary, in so far as the same may fall within the spirit and scope of the invention as expressed in the accompanying claims when broadly construed.

It will be understood of course that more than one fusible element can be employed by simply providing a set of slits "for each element, these being, angularly displaced, the ends of each element being led out through the slits as above explained, and

then brought into the circumferential formation by rotating the casing in the hand; this causes the projecting ends to be placed in superposed arrangement. in producing the exposed ortion of the fusible element structure. T e arrangement simply duplicates the single element arrangement disclosed, excepting that the exposed ends are not brought around the casing individually but together.

Having thus described my invention, what I claim as new is:

1. A fuse comprising a tubular casing of insulating material, and a fusible element of strip form having its end portions integral therewith and exposed externally and circumferentially of the fuse and an intermediate portion traversing the interior of the casing in the direction of casing length, the width of such strip ends being sufficient to provide an extended surface in the direction of length of the casing.

2. In refillable fuses, an open ended tubular casing of insulating material, and a fusible element of strip form having its end portions exposed externally and circumferentially of the casing ends and an intermediate portion traversing the interior of the casing in the direction of casing length, the cross-sectional width of the strip being sufficient to permit formation of bends therein effective to maintain the length of the longitudinally-extending portion of the strip, whereby the interior contents of the casing throughout its length will be limited to the fusible element.

3. A refillable fuse comprising a tubular casing of insulating material, and a fusible element of strip form having an intermediate portion traversing the casing in the direction of casing length, said strip having bends therein to maintain it in substantial axial relation to the tubular casing, said bends permitting the strip end portions to be led in directions angular to such intermediate portion to locate such end portions externally exposed on circumferential portions of the fuse.

4:. A fuse of the type of claim 3 charac terized in that the distance between the bends of the fusible element at the opposite ends of fuse is such as to maintain such bends within thelimits of the casing length while the intermediate portion of the element is intact.

5. In a refillable fuse, a tubular casing of insulating material having slits extending inwardly from the ends of the casing, and a fusible element extending longitudinally of the interior of the casing and having its end portions projecting through said slits and externally exposed on the outer Cll'? cumferential face of the casing, the width of such strip ends being sufiicient to provide I the two dimensions thereof of unequal length.

7. A refillable fuse comprising a tubular casing of insulating material, and a fusible element of strip form having a portion operative internally of the casing as a line protecting structure and extending externally of the casing in the form of circumferential fuse terminals, with each terminal of extended width to provide an extended contact surface.

8. A fuse as in claim 1 characterized in that the ends of the casing are closed by caps having their skirts overlying the easing and underlying the circumferential portions of the fusible element to locate the ends of the fusible element as external contacts of the fuse.

9. A fuse as in claim 1 characterized in that the fusible element end portions are maintained in position by an element in overlying relation thereto, with the overlying element of not greater width than the width of the fuse end.

10. A refillable fuse comprising a tubular casing of insulating material, said casing having slits extending inwardly from its ends, a fusible element extending longitudinally of the interior of the casing and having its ends extending through said slits, and end caps having their skirts overlying the casing and having slits adapted to register with the casing slits for the passage of said element ends, the ends of the element extending circumferentially about and externally of the cap skirts.

In testimony whereof I have hereto set my hand.

ALBERT F. DAU'M. 

